Learning about the brain, body and how it all connects

Main menu

Tag Archives: Insulin

Scientists have pursued every possible avenue to try to figure out why we keep getting fatter. They’ve explored our genes, our brains, our hormones and our gut bacteria, not to mention our fatty, sugary diets and sedentary lifestyles. Now, a recent study has come out blaming our expanding waistlines and poor health on our parents’ behaviors before we were born.

My newest article is up on The Atlantic, discussing recent research on the impact a mother’s diet has on her offspring’s health, affecting our brains and subsequently our bodies. This line of research isn’t new — otherstudies have shown links between a woman’s health during pregnancy and her child’s weight later in life — but this is one of the first to provide a potential explanation for this phenomenon by looking in the brain at some crucial hunger hormones.

However, you can’t blame all of your problems on your parents; what you eat still has a major impact on how these brain changes manifest:

Now, I’m all for shifting blame away from myself and onto my parents, but I feel that, like every possible explanation behind the obesity epidemic, this is only one piece of the puzzle. Genes undoubtedly play a role in body mass, fat percentage, and metabolism, but so does what you eat and how many calories you burn through physical activity…The problem of obesity, like so many health and social issues we face today, is that there isn’t just a single contributor to the problem. If there were, it would have been solved by now.

Two new papers have come out recently raising questions about eating-related disorders and their classification as psychological illnesses.

The first, published in Psychological Medicine, suggests that body dysmorphic disorder (BDD)–the tendency to have a warped sense of body image and to see problems in your body that are not there–is more indicative of a problem in the visual system than an issue with emotional self-image. BDD is most commonly described as a co-morbid disorder with anorexia, in which patients see themselves as much larger than they actually are, or as symptomatic of individuals who become addicted to plastic surgery.

Researchers at UCLA tested 14 participants diagnosed with BDD and 14 healthy controls on an fMRI study that involved viewing pictures of houses. The stimuli were manipulated to best represent either a generalized, holistic image of the house or to draw attention to more minute details, such as roof shingles. Participants with BDD demonstrated decreased activity in the prefrontal cortex when viewing the high detail images, and they had significantly less activation in the occipital lobe, or visual cortex, during the low detail pictures. The scientists conclude that this suggests patients with BDD allocate greater attention to detail and potentially have difficulty suppressing these types of thoughts. In addition, they may be unable to receive and process visual information from more holistic inputs, potentially indicative of a dissociation between global versus local visual processing.

The second paper, a recently published and already highly contested review article in the June issue of Molecular Psychiatry, asserts that anorexia is a metabolic disorder more akin to diabetes than extreme dieting. Lead author Donard Dwyer states that anorexia is a result of a “defective regulation of the starvation response, which leads to ambivalence towards food.” He argues that the levels of hormones in the body that regulate hunger and satiety are altered after prolonged starvation, resulting in a dysregulation of the feeding system and furthering dysfunctional eating behaviors.

In normal individuals, insulin is released when blood glucose levels get too low, triggering feelings of hunger and food-seeking behaviors. However, Dwyer posits that in anorexic patients these signals aren’t received, and the typical resulting urge to eat isn’t initiated. Early attempts at extreme dieting may spark this problem in those who are predisposed to metabolic dysfunction, creating a perpetuating cycle of self-induced starvation. In this way, anorexia is seen as more similar to diabetes, where a “western diet” of high fat and sugar can result in the insulin system shutting down in those with a genetic risk for the disease.

While his arguments about the hormonal changes that take place as a result of anorexia are plausible, it is difficult to swallow that the emotional and cognitive distress that accompany this disorder are a result of a malfunctioning metabolism. Starvation can result in the decay and death of cells in the brain and body, which Dwyer puts forth as the root for the co-morbid emotional and psychological symptoms seen in anorexic patients. However, the personality traits of perfectionism and anxiety so commonly seen in eating disorder patients typically exist before the eating symptoms begin. Additionally, when patients do recover, they frequently transition to a different type of eating disorder like bulimia, or they maintain an unhealthy obsession with food for the rest of their lives.

Dwyer’s position is partially in response to the question of why eating disorders are so pervasive and difficult to treat. Anorexia is notoriously persistent and has the highest percentage of death of any psychiatric illness. Many patients suffer for decades, constantly relapsing. A recent health article in the New York Times aptly compared anorexia to addiction, where patients never fully recover but instead remain in a constant state of remission. Attributing the disorder to a neurological or metabolic dysfunction rather than a mental health issue helps to explain why anorexia is so difficult to treat. However, just because there is a physical root to the problem does not make it any easier to cure. There are known neurological and anatomical abnormalities in schizophrenia, bipolar disorder, and depression, but that does not bring us any closer to solving these diseases. All we can do is try to treat the symptoms in the most efficient and effective way possible, whether that is through chemical, cognitive, or behavioral therapy, and hope for the best.